This study explored the mechanism of Xiangsha Liujunzi Decoction(XSLJZD) in the treatment of functional dyspepsia(FD) based on inositol-requiring enzyme 1(IRE1)/apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase(JNK) pathway-mediated autophagy in interstitial cells of Cajal(ICC). Forty-eight SPF-grade male SD suckling rats were randomly divided into a blank group and a modeling group, and the integrated modeling method(iodoacetamide gavage + disturbance of hunger and satiety + swimming exhaustion) was used to replicate the FD rat model. After the model replications were successfully completed, the rats were divided into a model group, high-dose, medium-dose, and low-dose groups of XSLJZD(12, 6, and 3 g·kg~(-1)·d~(-1)), and a positive drug group(mosapride of 1.35 mg·kg~(-1)·d~(-1)), and the intervention lasted for 14 days. The gastric emptying rate and intestinal propulsion rate of rats in each group were measured. The histopathological changes in the gastric sinus tissue of rats in each group were observed by hematoxylin-eosin(HE) staining. The ultrastructure of ICC was observed by transmission electron microscopy. The immunofluorescence double staining technique was used to detect the protein expression of phospho-IRE1(p-IRE1), TNF receptor associated factors 2(TRAF2), phospho-ASK1(p-ASK1), phospho-JNK(p-JNK), p62, and Beclin1 in ICC of gastric sinus tissue of rats in each group. Western blot was used to detect the related protein expression of gastric sinus tissue of rats in each group. Compared with those in the blank group, the rats in the model group showed decreased body weight, gastric emptying rate, and intestinal propulsion rate, and transmission electron microscopy revealed damage to the endoplasmic reticulum structure and increased autophagosomes in ICC. Immunofluorescence staining revealed that the ICC of gastric sinus tissue showed a significant elevation of p-IRE1, TRAF2, p-ASK1, p-JNK, and Beclin1 proteins and a significant reduction of p62 protein. Western blot revealed that the expression levels of relevant proteins in gastric sinus tissue were consistent with those of proteins in ICC. Compared with the model group, the body weight of rats in the high-dose and medium-dose groups of XSLJZD was increased, and the gastric emptying rate and intestinal propulsion rate were increased. Transmission electron microscopy observed amelioration of structural damage to the endoplasmic reticulum of ICC and reduction of autophagosomes, and the p-IRE1, TRAF2, p-ASK1, p-JNK, and Beclin1 proteins in the ICC of gastric sinus tissue were significantly decreased. The p62 protein was significantly increased. Western blot revealed that the expression levels of relevant proteins in gastric sinus tissue were consistent with those of proteins in ICC. XSLJZD can effectively treat FD, and its specific mechanism may be related to the inhibition of the expression of molecules related to the endoplasmic reticulum stress IRE1/ASK1/JNK pathway in ICC and the improvement of autophagy to promote gastric motility in ICC.
Animals ; Male ; Drugs, Chinese Herbal/administration & dosage* ; Autophagy/drug effects* ; Rats ; Rats, Sprague-Dawley ; Interstitial Cells of Cajal/metabolism* ; Dyspepsia/physiopathology* ; Protein Serine-Threonine Kinases/genetics* ; MAP Kinase Kinase Kinase 5/genetics* ; MAP Kinase Signaling System/drug effects* ; Humans ; Endoribonucleases/genetics* ; Multienzyme Complexes

OBJECTIVE: To investigate the effects of astragaloside IV (AS-IV) on podocyte injury of diabetic nephropathy (DN) and reveal its potential mechanism. METHODS: In in vitro experiment, podocytes were divided into 4 groups, normal, high glucose (HG), inositol-requiring enzyme 1 (IRE-1) α activator (HG+thapsigargin 1 µmol/L), and IRE-1α inhibitor (HG+STF-083010, 20 µmol/L) groups. Additionally, podocytes were divided into 4 groups, including normal, HG, AS-IV (HG+AS-IV 20 µmol/L), and IRE-1α inhibitor (HG+STF-083010, 20 µmol/L) groups, respectively. After 24 h treatment, the morphology of podocytes and endoplasmic reticulum (ER) was observed by electron microscopy. The expressions of glucose-regulated protein 78 (GRP78) and IRE-1α were detected by cellular immunofluorescence. In in vivo experiment, DN rat model was established via a consecutive 3-day intraperitoneal streptozotocin (STZ) injections. A total of 40 rats were assigned into the normal, DN, AS-IV [AS-IV 40 mg/(kg·d)], and IRE-1α inhibitor [STF-083010, 10 mg/(kg·d)] groups (n=10), respectively. The general condition, 24-h urine volume, random blood glucose, urinary protein excretion rate (UAER), urea nitrogen (BUN), and serum creatinine (SCr) levels of rats were measured after 8 weeks of intervention. Pathological changes in the renal tissue were observed by hematoxylin and eosin (HE) staining. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expressions of GRP78, IRE-1α, nuclear factor kappa Bp65 (NF-κBp65), interleukin (IL)-1β, NLR family pyrin domain containing 3 (NLRP3), caspase-1, gasdermin D-N (GSDMD-N), and nephrin at the mRNA and protein levels in vivo and in vitro, respectively. RESULTS: Cytoplasmic vacuolation and ER swelling were observed in the HG and IRE-1α activator groups. Podocyte morphology and ER expansion were improved in AS-IV and IRE-1α inhibitor groups compared with HG group. Cellular immunofluorescence showed that compared with the normal group, the fluorescence intensity of GRP78 and IRE-1α in the HG and IRE-1α activator groups were significantly increased whereas decreased in AS-IV and IRE-1α inhibitor groups (P<0.05). Compared with the normal group, the mRNA and protein expressions of GRP78, IRE-1α, NF-κ Bp65, IL-1β, NLRP3, caspase-1 and GSDMD-N in the HG group was increased (P<0.05). Compared with HG group, the expression of above indices was decreased in the AS-IV and IRE-1α inhibitor groups, and the expression in the IRE-1α activator group was increased (P<0.05). The expression of nephrin was decreased in the HG group, and increased in AS-IV and IRE-1α inhibitor groups (P<0.05). The in vivo experiment results revealed that compared to the normal group, the levels of blood glucose, triglyceride, total cholesterol, BUN, blood creatinine and urinary protein in the DN group were higher (P<0.05). Compared with DN group, the above indices in AS-IV and IRE-1α inhibitor groups were decreased (P<0.05). HE staining revealed glomerular hypertrophy, mesangial widening and mesangial cell proliferation in the renal tissue of the DN group. Compared with the DN group, the above pathological changes in renal tissue of AS-IV and IRE-1α inhibitor groups were alleviated. Quantitative RT-PCR and Western blot results of GRP78, IRE-1α, NF-κ Bp65, IL-1β, NLRP3, caspase-1 and GSDMD-N were consistent with immunofluorescence analysis. CONCLUSION AS-IV could reduce ERS and inflammation, improve podocyte pyroptosis, thus exerting a podocyte-protective effect in DN, through regulating IRE-1α/NF-κ B/NLRP3 signaling pathway.
Podocytes/metabolism* ; Animals ; Diabetic Nephropathies/metabolism* ; Saponins/therapeutic use* ; Triterpenes/therapeutic use* ; Signal Transduction/drug effects* ; NF-kappa B/metabolism* ; Protein Serine-Threonine Kinases/metabolism* ; Male ; Rats, Sprague-Dawley ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Endoribonucleases/metabolism* ; Endoplasmic Reticulum Chaperone BiP ; Rats ; Diabetes Mellitus, Experimental/complications* ; Endoplasmic Reticulum/metabolism* ; Multienzyme Complexes

OBJECTIVES: Uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is a progressive neurodegenerative disease associated with homozygous or compound heterozygous missense mutations in the GNE gene. This study aims to explore the impact of the homozygous p.V543M mutation in on cell phenotype and to gain preliminary insights into the underlying mechanisms. METHODS: Human embryonic kidney 293T (HEK 293T) cells were used to construct wild-type (WT-GNE) and mutant (MUT-GNE) GNE overexpression models. Western blotting and immunofluorescence were used to assess GNE protein expression levels and subcellular localization. Cell adhesion, proliferation, apoptosis, and mitochondrial membrane potential were evaluated using the cell counting kit-8 (CCK-8) assay, crystal violet staining, flow cytometry, Hoechst 33342/propidium iodide (PI) staining, and tetramethylrhodamine ethyl ester (TMRE) staining. Sialic acid synthesis levels and GNE enzymatic activity were measured, and the mRNA expression of sialic acid biosynthesis-related enzymes was quantified by real-time PCR. RESULTS: Western blotting confirmed successful establishment of GNE overexpression models. Immunofluorescence showed significantly reduced co-localization of GNE protein with Golgin-97 in the MUT-GNE group compared to WT-GNE (Pearson's correlation coefficient: 0.65±0.08 vs 0.83±0.06, P<0.05). Compared with WT-GNE, cells in the MUT-GNE group exhibited increased adhesion, decreased proliferation, and reduced mitochondrial membrane potential (P<0.05). No significant differences in apoptosis were observed between groups. The MUT-GNE group showed reduced sialic acid production, significantly decreased kinase activity, and downregulated transcription of sialic acid biosynthesis-related enzymes compared to WT-GNE (P<0.001). CONCLUSIONS The p.V543M mutation in the GNE gene alters cellular phenotype by reducing GNE enzymatic activity and the transcription of sialic acid biosynthesis enzymes, ultimately impairing sialic acid production.
Humans ; Mutation, Missense ; HEK293 Cells ; Apoptosis/genetics* ; Phenotype ; Multienzyme Complexes/metabolism* ; Cell Proliferation ; Homozygote ; Cell Adhesion/genetics* ; Distal Myopathies/genetics*

L-tyrosine is one of the 20 amino acids that make up proteins and is an essential amino acid for mammals, often used as a nutritional supplement. The conventional methods for synthesizing L-tyrosine have some problems such as the production of many by-products, high requirements for production conditions, and environmental pollution. In this study, we designed and constructed a multi-enzyme cascade for the synthesis of L-tyrosine with alanine, glutamate, ammonium chloride, and phenol as substrates. Initially, the sources of glutamate oxidase, alanine aminotransferase, and tyrosine phenol lyase were screened and analyzed, which was followed by the identification of the rate-limiting enzyme in the reaction process. A colorimetric screening method was established, and the rate-limiting enzyme DbAlaA was engineered to enhance its activity by 40.0%. Subsequently, the reaction conditions, including temperature, pH, cell concentration, and surfactant and coenzyme dosages, were optimized. After optimization, the yield of L-tyrosine reached 9.93 g/L, with a alanine conversion rate of 54.90%. Finally, a feed-batch fermentation strategy was adopted, and the yield of L-tyrosine reached 56.07 g/L after 24 h, with a alanine conversion rate of 65.22%. This study provides a reference for the whole-cell catalytic synthesis of L-tyrosine and its industrialization.
Tyrosine/biosynthesis* ; Escherichia coli/metabolism* ; Tyrosine Phenol-Lyase/genetics* ; Multienzyme Complexes/metabolism* ; Fermentation

L-phosphinothricin (L-PPT) is an efficient broad-spectrum herbicide. To realize the multi-enzyme catalytic preparation of L-PPT, we constructed an engineered strain Escherichia coli YM-1 for efficient expression of D-amino acid transaminase, which could catalyze the generation of the intermediate 2-oxo-4-[(hydroxymethylphosphonyl)] butyric acid (PPO) from D-phosphinothricin (D-PPT). In addition, E. coli pLS was constructed to co-express glutamate dehydrogenase and glucose dehydrogenase, which not only catalyzed the generation of L-PPT from PPO but also regenerated the coenzyme nicotinamide adenine dinucleotide phosphate (NADPH). A fed-batch fermentation process was then established for E. coli YM-1 and pLS, and the apparent activities of D-amino acid transaminase and glutamate dehydrogenase were increased by 22.68% and 100.82%, respectively, compared with those in shake flasks. The process parameters were optimized for the catalytic preparation of L-PPT by whole-cell cascade of E. coli YM-1 and pLS with D, L-PPT as the substrate. After reaction for 8 h, 91.36% conversion of D-PPT was achieved, and the enantiomeric excess of L-PPT reached 90.22%. The findings underpin the industrial production of L-PPT.
Escherichia coli/enzymology* ; Aminobutyrates/metabolism* ; Glutamate Dehydrogenase/biosynthesis* ; Glucose 1-Dehydrogenase/biosynthesis* ; Herbicides/metabolism* ; Multienzyme Complexes/metabolism* ; Transaminases/metabolism* ; Phosphinic Acids/metabolism*

Animals ; Autophagy/genetics* ; Cholesterol/metabolism* ; Gene Expression Regulation ; Integrases/metabolism* ; Leydig Cells/metabolism* ; Male ; Mice, Knockout ; Multienzyme Complexes/metabolism* ; Phosphoproteins/metabolism* ; Primary Cell Culture ; Progesterone Reductase/metabolism* ; RNA Splicing Factors/metabolism* ; Scavenger Receptors, Class B/metabolism* ; Sequestosome-1 Protein/metabolism* ; Signal Transduction ; Sirtuin 1/genetics* ; Sodium-Hydrogen Exchangers/metabolism* ; Steroid 17-alpha-Hydroxylase/metabolism* ; Steroid Isomerases/metabolism* ; Testosterone/genetics*

In vitro multi-enzyme molecular machines that follow the designed multi-enzyme pathways, require the rational optimization and adaptation of several purified or partially purified enzyme components, in order to convert certain substrates into target compounds in vitro in an efficient manner. This type of molecular machine is component-based and modularized, so that its design, assembly, and regulation processes are highly flexible. Recently, the advantages of in vitro multi-enzyme molecular machines on the precise control of reaction process and the enhancement of product yield have suggested their great application potential in biomanufacturing. Studies on in vitro multi-enzyme molecular machines have become an important branch of synthetic biology, and are gaining increasing attentions. This article systematically reviews the enzyme component-/module-based construction strategy of in vitro multi-enzyme molecular machines, as well as the research progress on the improvement of compatibility among enzyme components/modules. The current challenges and future prospects of in vitro multi-enzyme molecular machines are also discussed.
Biotechnology ; Enzymes ; chemistry ; metabolism ; Multienzyme Complexes ; chemistry ; metabolism ; Synthetic Biology

OBJECTIVETo study the association between endoplasmic reticulum stress (ERS) pathway mediated by inositol-requiring kinase 1 (IRE1) and the apoptosis of type II alveolar epithelial cells (AECIIs) exposed to hyperoxia.

METHODSThe primarily cultured AECIIs from preterm rats were devided into an air group and a hyperoxia group. The model of hyperoxia-induced cell injury was established. The cells were harvested at 24, 48, and 72 hours after hyperoxia exposure. An inverted phase-contrast microscope was used to observe morphological changes of the cells. Annexin V/PI double staining flow cytometry was performed to measure cell apoptosis. RT-PCR and Western blot were used to measure the mRNA and protein expression of glucose-regulated protein 78 (GRP78), IRE1, X-box binding protein-1 (XBP-1), and C/EBP homologous protein (CHOP). An immunofluorescence assay was performed to measure the expression of CHOP.

RESULTSOver the time of hyperoxia exposure, the hyperoxia group showed irregular spreading and vacuolization of AECIIs. Compared with the air group, the hyperoxia group showed a significantly increased apoptosis rate of AECIIs and significantly increased mRNA and protein expression of GRP78, IRE1, XBP1, and CHOP compared at all time points (P<0.05). The hyperoxia group had significantly greater fluorescence intensity of CHOP than the air group at all time points. In the hyperoxia group, the protein expression of CHOP was positively correlated with the apoptosis rate of AECIIs and the protein expression of IRE1 and XBP1 (r=0.97, 0.85, and 0.88 respectively; P<0.05).

CONCLUSIONSHyperoxia induces apoptosis of AECIIs possibly through activating the IRE1-XBP1-CHOP pathway.

Animals ; Apoptosis ; Cells, Cultured ; Endoplasmic Reticulum Stress ; physiology ; Endoribonucleases ; physiology ; Epithelial Cells ; physiology ; Female ; Hyperoxia ; metabolism ; pathology ; Multienzyme Complexes ; physiology ; Protein-Serine-Threonine Kinases ; physiology ; Pulmonary Alveoli ; pathology ; Rats ; Rats, Sprague-Dawley ; Transcription Factor CHOP ; physiology ; X-Box Binding Protein 1 ; physiology

The mitochondrial respiratory chain consists of 5 enzyme complexes that are responsible for ATP generation. The paradigm of the electron transport chain as discrete enzymes diffused in the inner mitochondrial membrane has been replaced by the solid state supercomplex model wherein the respiratory complexes associate with each other to form supramolecular complexes. Defects in these supercomplexes, which have been shown to be functionally active and required for forming stable respiratory complexes, have been associated with many genetic and neurodegenerative disorders demonstrating their biomedical significance. In this review, we will summarize the functional and structural significance of supercomplexes and provide a comprehensive review of their assembly and the assembly factors currently known to play a role in this process.
Adenosine Triphosphate ; metabolism ; Arylamine N-Acetyltransferase ; metabolism ; Cardiolipins ; metabolism ; Electron Transport ; Humans ; Mitochondria ; enzymology ; metabolism ; Multienzyme Complexes ; chemistry ; metabolism

Farnesoid X receptor (FXR) belongs to the nuclear receptor superfamily. It is highly related to the formation of metabolic syndrome and the glucose homeostasis, and therefore represents an important drug target against metabolic diseases and diabetes. In recent years, great progress has been made in the agonists, antagonists, and crystal structures of FXR. The diverse FXR ligands and their structure-activity relationship are reviewed in this article. The advances in the crystal structures of FXR in complex with different ligands are also introduced.
Animals ; Anticholesteremic Agents ; chemical synthesis ; chemistry ; pharmacology ; Azepines ; chemical synthesis ; chemistry ; pharmacology ; Benzene Derivatives ; chemical synthesis ; chemistry ; pharmacology ; Chenodeoxycholic Acid ; analogs & derivatives ; chemical synthesis ; chemistry ; pharmacology ; Crystallization ; Humans ; Indoles ; chemical synthesis ; chemistry ; pharmacology ; Isoxazoles ; chemical synthesis ; chemistry ; pharmacology ; Ligands ; Molecular Structure ; Multienzyme Complexes ; chemical synthesis ; chemistry ; pharmacology ; Pregnenediones ; chemical synthesis ; chemistry ; pharmacology ; Receptors, Cytoplasmic and Nuclear ; agonists ; antagonists & inhibitors ; metabolism ; Structure-Activity Relationship